JPS58158564A - Wiring testing for printed circuit board - Google Patents

Abstract

PURPOSE:To achieve an accurate inspection of wiring of a printed circuit board by measuring the resistance between a point on a printed circuit and a common electrode of a flat resistor after the board is pressurized on the flat resistor where a bar-shaped resistor body is arrayed vertically in a matrix. CONSTITUTION:A printed circuit board 1 is set on the upper portion of a flat resistor 13 where a bar-shaped resistor 14 is arranged and pressurized with a clamping device 16. A probe 10 is positioned with a X- and Y-double axis NC control mechanism and a voltage is applied between the probe 10 and a common electrode plate 15. Consequently, current flows between a land 18 and a circuit 11 and a land 19 and the common electrode plate 15 through a bar-shaped resistor 14 via a through hole 12. The current is measured with a resistance decision section 6 and compared with values of respecting circuits 11 prememorized into a control section 5 to determine the propriety of the circuits 11. According to this method, the condition of the wiring can be detected simply by measuring combined resistance values with only one probe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wiring test method for printed wiring boards.

With the increasing demand for printed wiring boards, the reduction in the number of different products, and the increase in density, it is an important issue to realize wiring tests efficiently (at low cost).

FIG. 1 is a diagram explaining the conventional wiring test method, in which spring gloves 3 corresponding to the total number of inspection points (two points at both ends of the circuit printed on the printed wiring board L) are placed on the glove array board. After aligning the 51fC probe array plate 8 so that the printed wiring board 1 and the spring probes 3 come into contact with the respective test points, apply pressure 2 to obtain an electrical connection and conduct a wiring test. was going on. That is, all spring globes 3 are wired to the scanner 4, and spring probes 30 corresponding to both ends of the circuit are connected by a scanner element (not shown) built in the scanner 4 driven by the control unit 5.
Two points were selected one after another, a voltage was applied, and the resistance value between the two points was measured by the resistance determination section 6, and the result was compared and determined with a normal value stored in the control section 5 in advance. Therefore, in the conventional wiring test method, since the scanner 4 selects a combination of two points across all inspection points on the printed wiring board 1 via the spring glove 3, the number of springs corresponding to the total number of inspection points is A scanner element built into the probe 3 and scanner 4 is required. In addition, there is a globe arrangement board 8 on which spring gloves 3 are arranged for each type of printing arrangement board 1.
It takes a lot of time to prepare and convert and connect the springs, which is extremely KA value for wiring tests of printed wiring boards 1 produced in high-mix, low-volume production. There were drawbacks such as it became difficult to arrange the probes 3 in a corresponding manner, and some printed wiring boards could not be subjected to cloth m tests.

The purpose of the present invention is to solve the above-mentioned drawbacks in a wiring testing method for printed wiring boards, and to provide a wiring testing method that is versatile and can be manufactured at low cost. Pressing a printed wiring board against a planar resistor in which rod-shaped resistors are arranged in a matrix in a direction perpendicular to the surface of the thin plate in a thin insulating elastic body, and at least one point on the same circuit on the printed wiring board; The wiring of the printed wiring board is inspected by applying a voltage between the planar resistor and the common electrode plate in contact with it and measuring the resistance value between each two points.

FIG. 2 is a diagram for basically explaining the wiring test method according to the present invention, and shows a planar resistor in which rod-shaped resistors 14 are arranged in a matrix in a direction perpendicular to the thin plate surface on a thin plate-shaped insulating elastic body. The body 13 is arranged in a sandwich-like manner between the printed wiring board 1 and the common electrode 15. Along with printed wiring board 1, 4
The electrode plate 15 is sandwiched between the planar resistor body 13 and pressurized by a clamping fitting 16. Upward movement and NC control on the X and Y axes (not shown)
The probe 10 that is being positioned comes into contact with a through hole 12 that serves as a circuit inspection point on the printed wiring board 1 and measures the resistance value. The control unit 6 determines the measurement results and also controls the glove 1.
00NC control is performed. Furthermore, the through holes 12 formed in the printed wiring board 1 are connected to the land 18, the circuit 11 and the land 1.
9 is connected.

3 and 4 explain that when a voltage is applied between the probe 10 and the common electrode plate J5 to the through hole 12 shown in FIG. 2, the measured resistance value changes depending on the area of the circuit 11. Fig. 3 is a diagram for representing the rod-shaped resistors 14 arranged on the planar resistor 13 as small circles, and the lands 18, circuits 11, and circuits 19 contact only the rod-shaped resistors 14 shown with diagonal lines. I am wearing clothes that are in a state of being.

FIG. 4 shows the number of circuits (N) between the globe 10 and the common electrode plate 15 of the rod-shaped resistor 14 shown by diagonal lines in FIG.
As a result, it becomes I-Mei.

The operation will be explained below with reference to the figures.The printed wiring board 1 is placed on top of the planar resistor 13 on which the rod-shaped resistors 14 are arranged, and pressurized with the clamping fitting 6. probe lO
NCI of Y2 axis! It is positioned and lowered using a 1IllI mechanism (not shown) and connected to the through hole 12. Next, a rod-shaped resistor 1 is inserted between the probe 10 and the common electrode plate 15.
Current flows through 4.

The number N of rod-shaped resistors 14 in contact with the circuit 11 is proportional to the area of the circuit 11, which is indicated by the diagonal line in FIG. It is indicated by the value W=-. Then, this W is measured by the resistance determination unit 6, and a comparison is made between the upper limit value, which is obtained by adding an allowable error from the expected resistance value for each circuit 11 stored in advance in the control unit 5, and the lower limit value, which is obtained by subtracting it. Judgment is made as to whether each ll is good or bad. In other words, if the measured resistance value J (is within the range between the upper limit value and lower limit value stored in the control unit 5), it is determined to be a good product, and if the upper limit value is higher than the measured resistance value] 7, a disconnection has occurred in the circuit 11. On the other hand, if it is lower than the lower limit value, it means that a short circuit has occurred between the circuit 11 and another circuit (not shown). For all the circuits 11 formed on the distribution board 1, there is one through hole 12 representing each circuit 11.
The globe 10 is sequentially moved by the NC control mechanism,
By marking the voltage, a wiring test of the printed wiring board 1 can be performed. As explained above, according to the present invention, a voltage is applied to one test point of a printed wiring board circuit using one probe, and the probe is moved onto each circuit one after another to obtain a combined resistance value H.
It is possible to determine the wiring condition of each circuit, that is, breakage or short circuit with other circuits, by simply measuring Since the confectionery is not required, the manufacturing cost of the wiring test method can be significantly reduced by 1", and it can be applied extremely efficiently as a general-purpose curve machine to printed wiring boards produced in large quantities and in small quantities. Furthermore, even if the printed layout board is coated with a solder resist, the land 19 connected to the land 18 in VC in FIG. The present invention brings extremely great effects, such as being able to perform a wiring test in a similar manner by applying a voltage to the section.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the conventional wiring test method, Fig. 2 is a diagram for explaining the basic wiring test method according to the present invention, and Figs. 3 and 4 are for explaining the wiring test method according to the present invention. FIG. 6 is a diagram for explaining that the measured resistance value changes depending on the area of the circuit when a Kit pressure is applied between the common electrode plate and the circuit. In the figure, l is a printing arrangement board, 2 is a pressurizing force 3 is a spring globe, 4 is a scanner group, 5 is a control section, 6 is a resistance determination section, 8 is a globe arrangement board, 10 is a vertical drive and X. Voltage 14 moved by control of Y two-axis NC1111] Application globe, 11 is a circuit formed on a printed wiring board, 12 and 17 are through holes, 13 is a planar resistor, 14 is a rod-shaped resistor, 15 is a common electrode plate, 16 is the fastening fitting, 18 and 19 are lands, K is the measured resistance value, R
is the resistance value of each rod-shaped resistor, and N is the number of rod-shaped resistors 14 that are in contact within the circuit area.

Claims (1)

[Claims] Pressing a printed wiring board against a planar resistor in which rod-shaped resistors are arranged in a matrix in a direction perpendicular to the surface of the thin plate in a thin insulating elastic body, and at least one point on the same circuit on the printed wiring board; The printed wiring is characterized in that the wiring inspection of the printed wiring board is performed by applying a voltage between the planar resistor and a common electrode plate in contact with each other and measuring the resistance value between each two points. Board wiring inspection method.